Hybrid wired and wireless communication system and a communication method thereof

ABSTRACT

A communication method for a hybrid wired and wireless communication system includes registering an entry comprising a physical address of a source transmitting a received packet and an identifier indicating a wired or wireless network interface linked to the physical address in a predetermined management list; receiving a transmission packet from an upper layer and determining whether a physical address identical with a destination physical address of the transmission packet is present in the management list; and when the destination physical address is present in the management list, transmitting the transmission packet through either of the wired network interface and the wireless network interface according to the identifier.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the priority of Korean Patent ApplicationNo. 2003-39890, filed on Jun. 19, 2003 in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a hybrid wired and wirelesscommunication system capable of performing both wired communication andwireless communication using a single physical address, and acommunication method thereof.

[0004] 2. Description of the Related Art

[0005] Generally, a hybrid wired and wireless communication systemincludes a central processing unit (CPU), a read-only memory (ROM), arandom-access memory (RAM), a peripheral device interface that can beconnected to peripheral devices, a wired network interface that can beconnected to a wired network, a wireless network interface that can beconnected to a wireless network, and protocol modules that cancommunicate with the wired network interface and the wireless networkinterface, respectively, all of which communicate across a bus.

[0006] To implement networking in a local area network (LAN) using thehybrid system, a network interface card (NIC) is required. The NICincludes a physical device (PHY) that is connected to an actual physicalmedia and can perform transmission/reception of a signal, and a mediaaccess control (MAC) module that performs MAC with respect to a mediumusing the PHY. The MAC module operates based on a physical address usedto communicate with another device in a network. A physical addressallocated to the NIC is stored in a ROM such as an electrically erasableprogrammable ROM (EEPROM) or a non-volatile RAM (NVRAM) in a system.

[0007] A LAN driver performs packet transmission/reception through anetwork and is present in an upper layer above the NIC. The LAN driveris connected to a protocol module in an upper protocol layer, whichperforms packet flow control and packet transfer, via a network driverinterface. The NIC includes a wired MAC with associated PHY and awireless MAC with associated PHY. The protocol layer includes TCP/IP andIPX/SPX protocols. A connection is secured using socket layer forprotocols such as HTTP, FTP, and POP 3.

[0008] The NIC has a 48-bit fixed physical address, and the protocolmodule in layer uses a logical address such as an Internet Protocol (IP)address to designate an address. The physical address and the logicaladdress allow the system to be identified in the network. The physicaladdress is stored in an area such as ROM in the system duringmanufacturing and is transmitted to the MAC module during systeminitialization.

[0009] In an Ethernet frame, a destination physical address indicates aMAC address of a host to receive data. A source physical addressindicates a MAC address of a host transmitting the data. Here, in eachof the destination and source physical addresses which comprise 48 bits,respectively, if a first bit is 0, the data is unicast (i.e.,transmitted to only one receiving host in the network). If the first bitis 1, the data is multicast (i.e., transmitted to only one certain hostsin the network). If all of the 48 bits are 1, the data is broadcast toall of hosts in the network. Also included are a frame type and a framecheck sequence (FCS).

[0010] Before the data is transmitted through the network, an addressused in a current layer is embedded into a header of a packet. Areceiving party analyzes the address embedded into the header anddetermines whether the data has been received correctly. If the addressembedded into the header is not identical with the receiving party'saddress, the receiving party does not receive the packet or discards thereceived packet without processing it.

[0011] In a system connected to a network, a packet received via an NICis transmitted to an application program via a protocol module of alayer bound with the NIC. Data generated in the application program istransmitted to the network via the protocol module and the NIC.

[0012] A wireless network interface may be set in an infrastructure modeor an ad-hoc mode. In the ad-hoc mode, a host can communicate withanother host wirelessly in a network. In the infrastructure mode, a hostcan be interlocked with another network via an access point (AP).

[0013] Specifically, when a hybrid wired and wireless communicationsystem wirelessly communicates with another communication system throughthe AP, the wireless communication mode in which the hybrid wired andwireless communication system wirelessly communicates with other typesof communication systems not directly but via the AP or the like isreferred to as the infrastructure mode. In contrast, when the hybridwired and wireless communication system wirelessly communicates with theanother communication system directly not via the AP, the wirelesscommunication mode is referred to as the ad-hoc mode.

[0014] As described above, the hybrid wired and wireless communicationsystem can be simultaneously connected to a wired network and a wirelessnetwork by using individual wired and wireless network interfaces. Here,each network interface needs a physical address identifying the networkinterface in a network. In other words, the hybrid wired and wirelesscommunication system shown in has two or more MAC modules, and two ormore physical addresses allocated to the two or more MAC modules,respectively.

[0015] To overcome this disadvantage, a hybrid wired and wirelesscommunication system using a single physical address has beenintroduced. Such hybrid wired and wireless communication system includesindividual MAC modules, but stores only one physical address in anassociated memory. Further, the system allocates the same physicaladdress to the individual MAC modules. In such a structure, since theindividual MAC modules use the same physical address, they arerecognized as the same unit by other devices on a network. Accordingly,when the hybrid wired and wireless communication system using a singlephysical address is connected to a wired network and the wirelessnetwork interface operates in the infrastructure mode, a double link ismade. Therefore, packet transmission/reception through the wirelessnetwork interface is interrupted.

[0016] However, when the wireless network interface operates in thead-hoc mode, packet transmission/reception through the wireless networkinterface can be performed even though the hybrid wired and wirelesscommunication system is connected to the wired network. While usable,when the hybrid wired and wireless communication system using a singlephysical address is connected to the wired network and its wirelessnetwork interface operates in the ad-hoc mode, a protocol module in anupper layer above the NIC cannot determine a network interface throughwhich a packet will be transmitted. As a result, the hybrid wired andwireless communication system transmits data through both of the wiredand wireless network interfaces, and a packet is redundantly transmittedthrough the wired and wireless networks. Consequently, traffic of onenetwork is loaded onto another network, which causes unnecessarydissipation of a bandwidth.

SUMMARY OF THE INVENTION

[0017] An aspect of the present invention provides a hybrid wired andwireless communication system which is connected to a wired network anda wireless network using a single physical address and prevents trafficof one network from being loaded onto another network when the system isconnected to a wired network and simultaneously a wireless networkinterface of the system operates in an ad-hoc mode, thereby preventingunnecessary dissipation of a bandwidth, and a communication methodthereof.

[0018] According to an aspect of the present invention, there isprovided a communication method for a hybrid wired and wirelesscommunication system capable of communicating by wire and wirelessly ina local area network, the communication method comprising: registeringan entry comprising a physical address of a source transmitting areceived packet and an identifier indicating a wired or wireless networkinterface linked to the physical address in a predetermined managementlist; receiving a transmission packet from an upper layer anddetermining whether a physical address identical with a destinationphysical address of the transmission packet is present in the managementlist; and when the destination physical address is present in themanagement list, transmitting the transmission packet through either ofthe wired network interface and the wireless network interface accordingto the identifier.

[0019] According to an aspect of the present invention, the entryfurther comprises a timer indicating duration from generation to removalof the entry in the management list.

[0020] According to an aspect of the present invention, the registeringof the entry comprises: determining whether the source physical addressof the received packet is present in the management list; when thesource physical address is not present in the management list,registering the source physical address and the identifier in themanagement list; transmitting the received packet to the upper layer;and determining whether a new packet has been received through either ofthe wired network interface and the wireless network interface andrepeating the determining of whether the source physical address ispresent, the registering of the source physical address and theidentifier, and the transmitting of the received packet.

[0021] According to an aspect of the present invention, the entryfurther comprises a timer indicating the duration from generation toremoval of the entry in the management list, and wherein the determiningof whether the source physical address is present comprises resettingthe timer to a predetermined initial value when it is determined thatthe source physical address of the received packet is present in themanagement list.

[0022] According to an aspect of the present invention, the operation ofreceiving the transmission packet and determining whether the physicaladdress identical with the destination physical address of thetransmission packet is present comprises: receiving the transmissionpacket from the upper layer and determining whether a type of thedestination physical address indicates a unicast transmission; andtransmitting the transmission packet through both of the wired networkinterface and the wireless network interface when it is determined thatthe type of the destination physical address does not indicate theunicast transmission and determining whether the physical address isidentical with the destination physical address of the transmissionpacket is present in the management list when it is determined that thetype of the destination physical address indicates the unicasttransmission.

[0023] According to another aspect of the present invention, there isprovided a hybrid wired and wireless communication system capable ofcommunicating by wire and wirelessly in a local area network, the hybridwired and wireless communication system comprising: a storage unitstoring a management list comprising a plurality of entries, each of theentries comprising a physical address of a source transmitting areceived packet and an identifier indicating a wired or wireless networkinterface linked to the physical address; a management moduledetermining whether a physical address identical with a source physicaladdress included in a received packet is present in the management list,registering the physical address and an identifier corresponding to thephysical address in the management list when it is determined that thephysical address is not present in the management list, and transmittingthe received packet to an upper layer; a control module receiving atransmission packet from the upper layer and selectively transmittingthe transmission packet through the corresponding one of the wirednetwork interface and the wireless network interface according to anidentifier corresponding to a destination physical address of thetransmission packet when the destination physical address is present inthe management list; and a wired network interface and a wirelessnetwork interface transmitting the received packet to the managementmodule, receiving the transmission packet from the control module, andtransmitting the transmission packet to networks, respectively,connected thereto.

[0024] According to an aspect of the present invention, the entryfurther comprises a timer indicating the duration from generation toremoval of the entry in the management list.

[0025] According to an aspect of the present invention, the controlmodule checks a type of the destination physical address of thetransmission packet received from the upper layer, transmits thetransmission packet through both of the wired network interface and thewireless network interface when the type of the destination physicaladdress does not indicate a unicast transmission, and determines whethera physical address identical with the destination physical address ispresent in the management list when the type of the destination physicaladdress indicates the unicast transmission.

[0026] According to an aspect of the present invention, the controlmodule transmits the transmission packet through both of the wirednetwork interface and the wireless network interface when thedestination physical address is not present in the management list.

[0027] Additional aspects and/or advantages of the invention will be setforth in part in the description which follows and, in part, will beobvious from the description, or may be learned by practice of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and/or other features and advantages of the presentinvention will become more apparent and more readily appreciated bydescribing in detail embodiments thereof with reference to theaccompanying drawings in which:

[0029]FIG. 1 is a block diagram of a hybrid wired and wirelesscommunication system;

[0030]FIG. 2 is a block diagram of a network system;

[0031]FIG. 3 illustrates a structure of an Ethernet frame;

[0032]FIG. 4A illustrates a network in an infrastructure mode;

[0033]FIG. 4B illustrates a network in an ad-hoc mode;

[0034]FIG. 5 is a block diagram of a hybrid wired and wirelesscommunication system according to an embodiment of the presentinvention;

[0035]FIG. 6 illustrates a structure of a management list according toan embodiment of the present invention;

[0036]FIG. 7 is a flowchart of a system initialization procedureaccording to an embodiment of the present invention;

[0037]FIG. 8 is a flowchart of a communication method when a wirelesscommunication mode is the ad-hoc mode, according to an embodiment of thepresent invention;

[0038]FIG. 9 is a detailed flowchart of an operation of generating amanagement list and registering a physical address shown in FIG. 8; and

[0039]FIG. 10 is a flowchart of an operation of managing an entry in amanagement list that is performed by a storage unit shown in FIG. 5according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] Reference will now be made in detail to the embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. Hereinafter, embodiments of the present invention will bedescribed in detail with reference to the attached drawings to explainaspects of the present invention.

[0041] As show in FIG. 1, a hybrid wired and wireless communicationsystem includes a central processing unit (CPU) 110, a read-only memory(ROM) 120, a random-access memory (RAM) 150, a peripheral deviceinterface 160 that can be connected to peripheral devices (not shown), awired network interface 130 that can be connected to a wired network140, a wireless network interface 170 that can be connected to awireless network 180, and protocol modules that can communicate with thewired network interface 130 and the wireless network interface 170,respectively, all of which communicate across a bus 190.

[0042] To implement networking in a local area network (LAN) using thesystem of FIG. 1, a network interface card (NIC) is required. The NICincludes a physical device (PHY) that is connected to an actual physicalmedia and can perform transmission/reception of a signal, and a mediaaccess control (MAC) module that performs MAC with respect to a mediumusing the PHY. The MAC module operates based on a physical address usedto communicate with another device in a network. A physical addressallocated to the NIC is stored in a ROM such as an electrically erasableprogrammable ROM (EEPROM) or a non-volatile RAM (NVRAM) in a system.

[0043] Referring to FIG. 2, a LAN driver 250 performing packettransmission/reception through a network is present in an upper layerabove the NIC 260. The LAN driver 250 is connected to a protocol modulein an upper protocol layer 230, which performs packet flow control andpacket transfer, via a network driver interface 240. As shown, the NIC260 includes a wired MAC 262 with associated PHY 264 and a wireless MAC266 with associated PHY 268. In the shown embodiment, the protocol layer230 includes TCP/IP and IPX/SPX protocols. A connection is secured usingsocket layer 220 for protocols 210 such as HTTP, FTP, and POP 3.

[0044] The NIC 260 has a 48-bit fixed physical address, and the protocolmodule in layer 230 uses a logical address such as an Internet Protocol(IP) address to designate an address. The physical address and thelogical address allow the system to be identified in the network. Thephysical address is stored in an area such as ROM 120 in the systemduring manufacturing and is transmitted to the MAC module 262, 266during system initialization.

[0045]FIG. 3 illustrates a structure of an Ethernet frame. Referring toFIG. 3, a destination physical address 310 in the Ethernet frameindicates a MAC address of a host to receive data 340. A source physicaladdress 320 indicates a MAC address of a host transmitting the data 340.Here, in each of the destination and source physical addresses 310, 320which comprise 48 bits, respectively, if a first bit is 0, the data 340is unicast (i.e., transmitted to only one receiving host in thenetwork). If the first bit is 1, the data 340 is multicast (i.e.,transmitted to only one certain hosts in the network). If all of the 48bits are 1, the data 340 is broadcast to all of hosts in the network.Also included are a frame type 330 and a frame check sequence (FCS) 350.

[0046] Before the data is transmitted through the network, an addressused in a current layer is embedded into a header of a packet. Areceiving party analyzes the address embedded into the header anddetermines whether the data has been received correctly. If the addressembedded into the header is not identical with the receiving party'saddress, the receiving party does not receive the packet or discards thereceived packet without processing it.

[0047] In a system connected to a network, a packet received via an NIC260 is transmitted to an application program via a protocol module of alayer 230 bound with the NIC 260. Data generated in the applicationprogram is transmitted to the network via the protocol module 230 andthe NIC 260.

[0048] A wireless network interface may be set in an infrastructure modeor an ad-hoc mode. In the ad-hoc mode, a host can communicate withanother host wirelessly in a network. In the infrastructure mode, a hostcan be interlocked with another network via an access point (AP).

[0049] Operations in the ad-hoc mode and in the infrastructure mode willbe described with reference to FIGS. 4A and 4B below. FIG. 4Aillustrates a network in the infrastructure mode. The network includescommunication systems 400, 402, 404, 408, and 409 and an AP 406 as shownin FIG. 1.

[0050] Among the communication systems 400, 402, 404, 408, and 409 shownin FIG. 4A, one is a hybrid wired and wireless communication system, andthe others are other types of communication systems that can communicateby wire and wirelessly with the hybrid wired and wireless communicationsystem of FIG. 1. For example, where the communication system 408 is thehybrid wired and wireless communication system, when the hybrid wiredand wireless communication system 408 wirelessly communicates with thecommunication system 402, the hybrid wired and wireless communicationsystem 408 wirelessly communicates with the AP 406, and thencommunicates with the communication system 402 via the AP 406.Meanwhile, where the communication system 400 is the hybrid wired andwireless communication system of FIG. 1, the hybrid wired and wirelesscommunication system 400 communicates by wire with the communicationsystems 402 and 404, and wirelessly communicates with communicationsystems 408 and 409 via the AP 406.

[0051] As described above in FIG. 4A, a wireless communication mode inwhich the hybrid wired and wireless communication system wirelesslycommunicates with other types of communication systems not directly butvia the AP 406 or the like is referred to as the infrastructure mode.

[0052]FIG. 4B illustrates a network in the ad-hoc mode. The networkincludes communication systems 410, 412, and 414. Among thecommunication systems 410, 412, and 414 shown in FIG. 4B, one is thehybrid wired and wireless communication system of FIG. 1, and the othersare other types of communication systems that can communicate by wireand wirelessly with the hybrid wired and wireless communication system.For example, when a hybrid wired and wireless communication system 410wirelessly communicates with the other communication systems 412 and414, the hybrid wired and wireless communication system 410 wirelesslycommunicates with the other communication systems 412 and 414 directlynot via the AP 406 shown in FIG. 4A or the like. As described above, awireless communication mode in which a hybrid wired and wirelesscommunication system wirelessly communicates with another communicationsystem directly without requiring a relay such as the AP 406 is referredto as the ad-hoc mode.

[0053] As described above, the hybrid wired and wireless communicationsystem can be simultaneously connected to a wired network 140 and awireless network 180 by using individual wired and wireless networkinterfaces 130, 170 as shown in FIG. 1. Here, each network interface 260shown in FIG. 2 needs a physical address identifying the networkinterface in a network. In other words, the hybrid wired and wirelesscommunication system shown in FIGS. 1 and 2 has two or more MAC modules262, 266 using a single physical address.

[0054] Referring to FIG. 5, a hybrid wired and wireless communicationsystem includes a wired network interface 510 connected to a wirednetwork 500, a wireless network interface 530 connected to a wirelessnetwork 520, a management module 540, a storage unit 550, and a controlmodule 560. The management module 540 receives packets through the wirednetwork interface 510 and the wireless network interface 530, registersa physical address of a source of a received packet in the managementlist, and transmits the received packet to an upper layer. The storageunit 550 stores and updates a management list including a plurality ofmanagement entries. Each of the entries includes a physical address of asource of a received packet and an interface number indicating which ofthe wired network interface 510 or the wireless network interface 530 islinked to the physical address. The control module 560 receives atransmission packet from an upper layer, checks whether a physicaladdress of a source of the transmission packet is present in themanagement list stored in the storage unit 550, and selectivelytransmits the transmission packet through the wired or wireless networkinterface 510 or 530 according to an interface number linked to thephysical address in the management list when the physical address ispresent in the management list. The management module 540 and thecontrol module 560 are implemented on a local area network (LAN) drivershown in FIG. 2, which is easily understood by those skilled in the art.While not shown, it is understood that the CPU 110, ROM 120, Interface160, RAM 150, and/or BUS 190 of FIG. 1 are included in the system shownin FIG. 5 according to an aspect of the invention. However, it isunderstood that the system can be otherwise configured and/or used withthe network types beyond LAN, such as wide area networks (WAN), publicand private networks such as the internet and intranets, and/or in anycommunication medium by which a device connected to the network utilizesidentification for transmission and/or reception of data.

[0055]FIG. 6 illustrates a structure of a management list stored in unit550 according to an embodiment of the present invention. Referring toFIG. 6, the management list includes a physical address item, aninterface number item, and a timer item. The shown management listfurther includes a type item indicating whether an entry is valid orinvalid according to the timer item but, need not include the typeand/or validity entry in all aspects of the invention. Further, it isunderstood that the management list could include additionalinformation, and that items in the management list could be combined toreduce the number of entries according to aspects of the invention.

[0056] A physical address in the management list indicates a mediaaccess control (MAC) address of a source that has transmitted a receivedpacket included in the packet frame shown in FIG. 3. In the shownembodiment of the present invention, the physical address is 48 bits inlength. However, it is understood that the physical address can haveother lengths and formats.

[0057] An interface number in the management list is an identifierindicating either the wired network interface 510 or the wirelessnetwork interface 530 that the received packet has been receivedthrough. In other words, the interface number indicates a networkinterface linked to the physical address. As shown, the identifiernumber “2” indicates the wired interface 510, and the identifier number“1” indicates the wireless interface 530.

[0058] An aspect of the present invention is proposed to preventunnecessary traffic from occurring since a transmission packet istransmitted through both of the wired and wireless network interfaces510 and 530 when a wireless communication mode is the ad-hoc mode in acase where wired and wireless MAC interfaces 262, 266 share the singlephysical address that otherwise occurs using the conventional system.Specifically, to prevent the occurrence of unnecessary traffic and othersuch problems, whenever a packet is received, the management listrecords a physical address of a source transmitting the packet and aninterface number indicating whether a network interface linked to thephysical address is wired or wireless. When a transmission packetgenerated in an upper layer is to be transmitted to a physical addresscorresponding to a physical address in the management list, thetransmission packet is transmitted through the corresponding indicatedone of the wired network interface 510 and the wireless networkinterface 530 according to the interface number linked to the physicaladdress in the management list. Accordingly, the physical address itemand the interface number item are essential to the management list inthe embodiment shown in FIG. 6. However, it is understood that, if thephysical address and identifier can be otherwise combined or where theidentifier of the interface 510, 530 can be otherwise correlated orconveyed using a single entry and/or other entry, the management listneed not include both the physical address and the identifier in theform shown in FIG. 6.

[0059] A timer indicates a duration from a generation of the entry whenthe physical address is added to the management list to a removal of theentry in the management list. A type indicates whether an entry is validand remains in the management list, or is invalid and is to be removedfrom the management list. It is understood that the type can alsoindicate other information of interest, and that the type need not beused, such as if the system removes the entry as soon as the durationindicates that the entry is to be removed.

[0060] In the shown embodiment of the present invention, to increasestorage efficiency of the management list, a time during which an entryis stored in the management list is set. In detail, the timer item isincluded in the management list, and an initial value of the timer itemis set. Thereafter, a value of the timer item is increased or decreased,and when a predetermined time lapses, an entry having an expiring timeris removed from the management list. Before a timer expires, if a packetis received from a physical address corresponding to the timer, thetimer is initialized. When a timer expires, a corresponding type is setto be invalid indicating that the entry is to be deleted, and the systemdeletes the entry. Otherwise, the type is set to be valid, indicatingthat the entry is remain. However, it is understood that the timerand/or type fields need not be used in all aspects of the invention,such as where a record of transmission and/or reception is desired.

[0061]FIG. 7 is a flowchart of a system initialization procedureaccording to an embodiment of the present invention. When a hybrid wiredand wireless communication system is supplied with electric power and isbooted, the system is initialized is in operation S700. In the systeminitialization, a single physical address stored in a memory unit (notshown) is transmitted to the LAN driver including the management module540 and the control module 560. The LAN driver allocates the physicaladdress to each network interface 510, 530 of the hybrid wired andwireless communication system to initialize a MAC module and theninitializes a transmitter and a receiver of each network interface 510,530.

[0062] After the system initialization in operation S700, the LAN driverchecks an operating mode and state of the wired network interface 510and the wireless network interface 530, and particularly checks whetherthe wireless communication mode is the ad-hoc mode (in operation S710).When the wireless communication mode is the ad-hoc mode, the managementmodule 540 is started in operation S720, and the control module 560 isstarted in operation S730. When the wireless communication mode is notthe ad-hoc mode, operations S720 and S730 are not performed.

[0063]FIG. 8 is a flowchart of a communication method when a wirelesscommunication mode is the ad-hoc mode according to an embodiment of thepresent invention. Referring to FIG. 8, the management module 540generates the management list shown in FIG. 6 using a received packetand registers a source physical address included in the received packetin the management list in operation S800. An embodiment of operationS800 will be described in detail with further reference to FIG. 9 below.

[0064] When a hybrid wired and wireless communication system is startedand the management module 540 is started in the ad-hoc mode, the storageunit 550 initializes the management list in operation S900. Thereafter,a packet receiver 542 included in the management module 540 determineswhether a packet has been received from a wired receiver 512 included inthe wired network interface 510 or a wireless receiver 532 included inthe wireless network interface 530 in operation S910. If it isdetermined that a packet has been received, an address checker 544included in the management module 540 checks a source physical addressincluded in the received packet to determine whether the source physicaladdress indicates a unicast transmission in operation S915.

[0065] If the source physical address indicates broadcast or multicasttransmission, the address checker 544 just transmits the received packetto an upper layer in operation S950 without performing operations S930or S920. If the source physical address indicates the unicasttransmission, the address checker 544 determines with reference to thestorage unit 550 whether the source physical address, (i.e., the sourceMAC address is present in the management list) in operation S920. It isunderstood, however, that operation S915 need not be performed such thatoperation S920 is performed regardless of whether the packet is unicast,broadcast, and/or multicast, and that operation S915 can be performedonly for selected ones of the unicast, multicast, and/or broadcast andnot for non-selected ones of the unicast, multicast, and broadcast.

[0066] If the source physical address is not present in the managementlist, the management module 540 registers the source physical addressand an interface number indicating a network interface linked to thesource physical address in the management list stored in the storageunit 550 in operation S930. By way of example, in the management listshown in FIG. 6, when the wireless network interface 530 is linked tothe source physical address, the interface number is set to “1”, andwhen the wired network interface 510 is linked to the source physicaladdress, the interface number is set to “2”. In addition, the managementmodule 540 sets a timer to an initial value in operation S930 andtransmits the received packet to the upper layer in operation S950.

[0067] Meanwhile, if the source physical address is present in themanagement list, the storage unit 550 initializes to the initial value atimer corresponding to the source physical address in operation S940 andthe management module 540 transmits the received packet to the upperlayer in operation S950.

[0068] Referring back to FIG. 8, after the management list is generated,the control module 560 is started and a packet transmitter 562 includedin the control module 560 determines whether a packet to be transmittedto a network has been received from the upper layer in operation S810.If the packet transmitter 562 has received the transmission packet fromthe upper layer, a list checker 564 included in the control module 560checks the transmission packet to determine whether a type of adestination physical address included in the transmission packetindicates unicast transmission, multicast transmission, or broadcasttransmission in operation S830. However, it is understood that operationS830 does not need to be performed in all aspects of the invention.

[0069] If the type of the destination physical address indicates themulticast or broadcast transmission, the packet transmitter transmitsthe transmission packet to both of the wired transmitter 514 and thewireless transmitter 534 so that the transmission packet is transmittedto both of the wired network 500 and the wireless network 520 inoperation S860. If the type of the destination physical addressindicates the unicast transmission, the list checker 564 determinesreferring to the storage unit 550 whether the destination physicaladdress of the transmission packet is present in the management list inoperation S840.

[0070] If the destination physical address of the transmission packet ispresent in the management list, the packet transmitter 562 transmits thetransmission packet to the destination address through the wired networkinterface 510 or the wireless network interface 530 according to aninterface number corresponding to the destination physical address inthe management list in operation S850. In detail, when the interfacenumber indicates the wired network interface 510, the packet transmitter562 transmits the transmission packet to the wired transmitter 514without transmitting through the wireless transmitter 534. When theinterface number indicates the wireless network interface 530, thepacket transmitter 562 transmits the transmission packet to the wirelesstransmitter 534 without transmitting through the wired transmitter 514.

[0071] Meanwhile, if the destination physical address of thetransmission packet is not present in the management list, the packettransmitter 562 transmits the transmission packet to both of the wiredtransmitter 514 and the wireless transmitter 534 so that thetransmission packet is transmitted to both of the wired and wirelessnetworks 500 and 520 in operation S860. However, it is understood that,instead of transmitting through both transmitters 514, 534, thetransmission could be through a default one of the transmitters 514, 534or through one of the transmitters 514, 534 having the least traffic.

[0072]FIG. 10 is a flowchart of an operation of managing an entry in amanagement list that is performed by the storage unit 550 according toan aspect of the invention. The storage unit 550 stores the managementlist. The storage unit 550 periodically checks a timer item in themanagement list in operation S1000, and determines whether any validentry is present in the management list in operation S1010.

[0073] The storage unit 550 determines whether any valid entry has anexpiring timer in operation S1020. If any valid entry has the expiringtimer, the storage unit 550 changes the valid entry into an invalidstate to indicate an entry which may be removed from the management listin operation 1030. If there is no entry having an expiring timer, anyvalid entry's timer is increased or decreased in operation S1040. Forexample, when an initial value of a timer is 20 and a value of 0 denotesexpiration of the timer, the timer is decreased by 1. Conversely, whenthe initial value of the timer is 0 and the value 20 denotes theexpiration, the timer is increased by 1. While not shown in FIG. 10,where the timer has expired, the storage unit 550 removes the entryhaving the expired timer according to an aspect. Additionally, the timerentry can be increased by 1 or reset where the physical address is againreceived so as to prevent the premature removal of an entry from themanagement list where the physical address relates to another systemwith respect to which packets are being transferred.

[0074] An aspect of the invention can also be embodied as computerreadable codes on a computer readable recording medium or media for usewith one or more computers. The computer readable recording medium isany data storage device that can store data which can be thereafter readby a computer system. Examples of the computer readable recording mediuminclude read-only memory (ROM), random-access memory (RAM), CD-ROMs,magnetic tapes, floppy disks, optical data storage devices, and carrierwaves (such as data transmission through the Internet). The computerreadable recording medium can also be distributed over network coupledcomputer systems so that the computer readable code is stored andexecuted in a distributed fashion.

[0075] It is understood that, according to an aspect of the invention,the management list can be otherwise updated and can be created by otherdevices without requiring reception of a packet from a source. Moreover,while shown as having two interfaces 510, 530, it is understood that themanagement list of an aspect of the present invention can be used with aplurality of interfaces for use in systems having multiple networkconnections and sharing a common address.

[0076] A hybrid wired and wireless communication system according to thepresent invention uses a single physical address for both of wired andwireless network interfaces, and whenever a packet is received, recordsa physical address of a source transmitting the packet and an interfacenumber indicating whether a network interface linked to the physicaladdress is wired or wireless in a management list. Thereafter, when atransmission packet generated in an upper layer is transmitted to thephysical address in the management list, the hybrid wired and wirelesscommunication system selectively transmits the transmission packetthrough either of the wired network interface and the wireless networkinterface according to the interface number linked to the physicaladdress in the management list. Therefore, an aspect of the presentinvention prevents traffic of one network from being loaded onto anothernetwork, thereby preventing dissipation of a bandwidth.

[0077] While aspects of the this invention has been particularly shownand described with reference to embodiments thereof, it will beunderstood by those skilled in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the invention as defined by the appended claims. The embodimentsshould be considered in the descriptive sense only and not for purposesof limitation. Therefore, the scope of the invention is defined not bythe detailed description of the invention, but by the appended claims,and all differences within the scope will be construed as being includedin the present invention, the scope of which is defined in the claimsand their equivalents.

What is claimed is:
 1. A communication method for a hybrid wired and wireless communication system capable of communicating by wire and wirelessly in a local area network, the communication method comprising: registering an entry comprising a source physical address of a source transmitting a received packet and an identifier indicating and distinguishing between a wired network interface and a wireless network interface linked to the physical address in a predetermined management list; receiving a transmission packet from an upper layer of the system and determining whether a registered physical address that is identical with a destination physical address of the received transmission packet is present in the management list; and when the destination physical address is present in the management list, selectively transmitting the transmission packet through the indicated one of the wired network interface and the wireless network interface according to the identifier.
 2. The communication method of claim 1, wherein the entry further comprises a timer indicating a duration from a generation of the entry in the management list to a removal of the entry from the management list.
 3. The communication method of claim 2, wherein the registering of the entry comprises: periodically checking a value of the timer to determine the duration until the timer expires; and removing the entry from the management list if the timer expires.
 4. The communication method of claim 1, wherein the registering of the entry comprises: determining whether the source physical address of the received packet is present in the management list; when the source physical address is not present in the management list, registering the source physical address and the identifier in the management list; transmitting the received packet to the upper layer; and determining whether a new packet has been received through either of the wired network interface and the wireless network interface and repeating the determining of whether the source physical address is present, the registering of the source physical address and the identifier, and the transmitting of the received new packet to the upper layer.
 5. The communication method of claim 4, wherein the entry further comprises a timer indicating a duration from a generation of the entry in the management list to a removal of the entry from the management list, and wherein the determining whether the source physical address is present further comprises resetting the timer to a predetermined initial value when the source physical address of the received packet is determined to be present in the management list at the time the received packet is received.
 6. The communication method of claim 1, wherein the operation of receiving the transmission packet and determining whether the physical address is identical with the destination physical address of the transmission packet is present comprises: receiving the transmission packet from the upper layer and determining whether a type of the destination physical address indicates a unicast transmission; transmitting the transmission packet through the wired network interface and the wireless network interface, when the type of the destination physical address is determined not to indicate the unicast transmission; and determining whether the physical address is identical with the destination physical address of the transmission packet is present in the management list, when the type of the destination physical address is determined to indicate the unicast transmission.
 7. The communication method of claim 1, wherein the transmitting of the transmission packet comprises transmitting the transmission packet through the wired network interface and the wireless network interface when the destination physical address is not present in the management list.
 8. The communication method of claim 1, wherein the registering of the entry, the operation of receiving the transmission packet and determining whether the physical address is identical with the destination physical address of the transmission packet is present, and the selectively transmitting the transmission packet through of the indicated one of the wired network interface and the wireless network interface according to the identifier are performed when a wireless communication mode of the hybrid wired and wireless communication system is an ad-hoc mode.
 9. The communication method of claim 1, wherein the wireless network interface and the wired network interface have a same physical address.
 10. A computer readable recording medium for storing a program code for executing in a computer a communication method for a hybrid wired and wireless communication system capable of communicating by wire and wirelessly in a local area network, the communication method comprising: registering an entry comprising a source physical address of a source transmitting a received packet and an identifier indicating and distinguishing between a wired network interface and wireless network interface linked to the physical address in a predetermined management list; receiving a transmission packet from an upper layer of the system and determining whether a registered physical address that is identical with a destination physical address of the transmission packet is present in the management list; and when the destination physical address is present in the management list, selectively transmitting the transmission packet through of the indicated one of the wired network interface and the wireless network interface according to the identifier.
 11. A hybrid wired and wireless communication system capable of communicating by wire and wirelessly in a local area network, the hybrid wired and wireless communication system comprising: an upper layer; a processor which receives and transmits packets received through the upper layer; a storage unit which stores a management list comprising a plurality of entries, each of the entries comprising a physical address of a source transmitting a received packet and an identifier indicating and distinguishing between a wired network interface and a wireless network interface linked to the physical address; a management module which determines whether a physical address that is identical with a source physical address included in a received packet is present in one of the entries the management list, registers the source physical address and an identifier corresponding to the physical address in a new entry of the management list when the physical address is determined to not be present in the management list, and transmitting the received packet to upper layer; a control module receiving a transmission packet from the upper layer and selectively transmitting the transmission packet through an indicated one of the wired network interface and the wireless network interface according to an identifier corresponding to a destination physical address of the transmission packet when the destination physical address is present in the management list; a wired network interface which transmits the received packet to the management module, and, if the control module controls the received packet to be transmitted through the wired network interface, receives the transmission packet from the control module and transmits the transmission packet to the wired network connected thereto; and a wireless network interface which transmits the received packet to the management module, and, if the control module controls the received packet to be transmitted through the wireless network interface, receives the transmission packet from the control module and transmits the transmission packet to the wireless network connected thereto.
 12. The hybrid wired and wireless communication system of claim 11, wherein each entry further comprises a timer indicating a duration from a generation of the entry to a removal of the entry in the management list.
 13. The hybrid wired and wireless communication system of claim 12, wherein the storage unit periodically checks a value of the timer of each entry to determine whether the timer has expired and, if the duration indicates that the entry has expired, removes the entry having expiring timer from the management list.
 14. The hybrid wired and wireless communication system of claim 12, wherein, when the source physical address is determined to be present in the management list when the received packed is received, the storage unit resets the timer of the entry corresponding to the source physical address to a predetermined initial value.
 15. The hybrid wired and wireless communication system of claim 11, wherein the control module further checks a type of the destination physical address of the transmission packet received from the upper layer, transmits the transmission packet through both of the wired network interface and the wireless network interface when the type of the destination physical address does not indicate a unicast transmission, and determines whether the physical address that is identical with the destination physical address is present in the management list when the type of the destination physical address indicates the unicast transmission.
 16. The hybrid wired and wireless communication system of claim 11, wherein the control module transmits the transmission packet through the wired network interface and the wireless network interface when the destination physical address is not registered in one of the entries in the management list.
 17. The hybrid wired and wireless communication system of claim 11, wherein the wireless network interface and the wired network interface have a same physical address.
 18. The hybrid wired and wireless communication system of claim 11, wherein the hybrid wired and wireless communication system operates when a wireless communication mode is an ad-hoc mode.
 19. A communication method for a hybrid communication system capable of communicating by a first network of a first type and by a second network of a second type other than the first type, the communication method comprising: for a transmission packet to be transmitted from the system to one of the first and second networks, determining which one of first and second interfaces is to be used to transmit the received transmission packet based on a comparison of a destination physical address of the transmission packet with a management list of the system; and selectively transmitting the transmission packet through the determined one of the first and second interfaces while not transmitting the transmission packet through the other one of the first and second interfaces.
 20. The communication method of claim 19, wherein the first type of network is a wired network, and the second type of network is a wireless network.
 21. The communication method of claim 19, further comprising: receiving at the system another packet from the destination physical address, and recording in the management list through which one of the first and second interfaces the another packet was received and the destination physical address.
 22. The communication method of claim 21, wherein the determining which one of first and second interfaces is to be used to transmit the transmission packet comprises: reviewing the destination physical address detected from the transmission packet and the management list to detect an entry of the management list that indicates through which one of the first and second interfaces the another packet was received from the destination physical address, and determining that the one of the first and second interfaces recorded in the detected entry is the one of the first and second interfaces through which the transmission packet is to be transmitted.
 23. The communication method of claim 19, wherein: the management list comprises first and second entries, the first entry comprises a first physical address and an indication that the first interface is to be used in transmitting to the first physical address, the second entry comprises a second physical address and an indication that the second interface is to be used in transmitting to the second physical address, and the determining which one of first and second interfaces is to be used to transmit the received transmission packet comprises: determining that the first interface is to be used if the destination physical address corresponds to the first physical address, and determining that the second interface is to be used if the destination physical address corresponds to the second physical address.
 24. The communication method of claim 19, wherein: the management list comprises a first entry comprising a first physical address, an indication indicating and distinguishing between which one of the first and second interfaces is to be used in transmitting to the first physical address, and a validity indication, and the communication method further comprises deleting the first entry if the validity indication indicates that the first entry is not valid.
 25. The communication method of claim 24, wherein the validity indication comprises a timer value which is decremented such that the system deletes the first entry a predetermined time after a time when the first entry was created.
 26. The communication method of claim 25, further comprising, if another packet is received from a same physical address as the first physical address, increasing the timer value.
 27. The communication method of claim 19, wherein the first and second interfaces share a common physical address such that a first packet received at the first interface through the first network is addressed to the common physical address and a second packet received at the second interface through the second network is addressed to the common physical address.
 28. A computer readable medium encoded with processing instructions for implementing the communication method of claim 19 performed by a computer.
 29. A communication system capable of communicating packets of data across a first network of a first type and a second network of a second type other than the first type, the communication system comprising: a first network interface which connects to the first network to transfer ones of the packets with respect to the first network; a second network interface which connects to the second network to transfer others of the packets with respect to the second network; a storage unit which stores a management list comprising a plurality of entries, each of the entries identifying and distinguishing between the first and second network interfaces; and a processor which compares a transmission packet to be transmitted and the entries of the management list, determines based on the comparison which one of the first and second network interfaces is to be used for transmission of the transmission packet, and controls the transmission packet to be transmitted through the determined one of the first and second network interfaces.
 30. The communication system of claim 29, wherein: the transmission packet includes a destination physical address, each of the entries includes a corresponding physical address and identifies and distinguishes between the first and second network interfaces, and the processor further determines whether one of the entries includes the physical address that is identical with the destination physical address included in the transmission packet, and controls the transmission packet to be transmitted through the indicated one of the first and second network interfaces included in the one entry having the identical physical address as the destination physical address.
 31. The communication system of claim 29, wherein the processor further, for a received packet having a source physical address, if the source physical address is a physical address not present in one of the entries of the management list, records a new entry in the management list including the source physical address and an identifier indicating through which one of the first and second network interfaces the received packet was received.
 32. The communication system of claim 29, wherein the first type of network is a wired network, and the second type of network is a wireless network.
 33. The communication system of claim 29, wherein: one of the entries further comprises a validity indication, and the processor further deletes the one entry if the validity indication indicates that the one entry is not valid.
 34. The communication system of claim 33, wherein the validity indication comprises a timer value, and the processor decrements the timer value such that the system deletes the one entry at a predetermined time after a time when the one entry was created.
 35. The communication system of claim 33, wherein: the one entry further includes a physical address and identifies and distinguishes between the first and second network interfaces, and the processor further adjusts the validity indication according to when the physical address in the one entry was last verified.
 36. The communication system of claim 35, wherein: if another packet is received and includes a physical address identical to the physical address indicated in the one entry, the processor verifies the validity indication to prevent deletion for an additional period of time.
 37. The communication system of claim 36, wherein: the validity indication comprises a timer value, and the processor decrements the timer value such that the system deletes the first entry at a predetermined time after a time when the one entry was created, and increments the time value if the validity indication is verified.
 38. The communication system of claim 29, wherein the first and second interfaces share a common physical address such that a first packet received at the first network interface through the first network is addressed to the common physical address and a second packet received at the second network interface through the second network is addressed to the common physical address.
 39. A communication system capable of communicating packets of data across a first network of a first type of and a second network of a second type other than the first type, the communication system comprising: a first network interface which connects to the first network to transfer ones of the packets with respect to the first network; a second network interface which connects to the second network to transfer others of the packets with respect to the second network; a storage unit which stores a management list comprising a plurality of entries, each of the entries identifying and distinguishing between the first and second network interfaces; and a processor which compares a received packet received through one of the first and second network interfaces and the entries of the management list, and, if the received packet is from a source physical address not included in the entries of the management list, records a new entry including the source physical address and an indication which indicates which one of the first and second network interfaces received the received packet.
 40. The communication system of claim 39, wherein the processor further controls a transmission packet to be transmitted through the first and second network interfaces according to the indication in the management list.
 41. The communication system of claim 39, wherein: one of the entries further comprises a validity indication, and the processor further deletes the one entry if the validity indication indicates that the one entry is not valid.
 42. The communication system of claim 41, wherein the validity indication comprises a timer value, and the processor decrements the timer value such that the system deletes the one entry at a predetermined time after a time when the one entry was created.
 43. The communication system of claim 41, wherein: the one entry further includes a physical address and identifies and distinguishes between the first and second network interfaces, and the processor further adjusts the validity indication according to when the physical address in the one entry was last verified.
 44. The communication system of claim 43, wherein: if another packet is received and includes a physical address identical to the physical address indicated in the one entry, the processor verifies the validity indication to prevent deletion for an additional period of time.
 45. The communication system of claim 44, wherein: the validity indication comprises a timer value, and the processor decrements the timer value such that the system deletes the first entry at a predetermined time after a time when the one entry was created, and increments the time value if the validity indication is verified.
 46. The communication system of claim 39, wherein the first and second interfaces share a common physical address such that a first packet received at the first network interface through the first network is addressed to the common physical address and a second packet received at the second network interface through the second network is addressed to the common physical address. 